create_upload_session

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description must carry the burden of behavioral disclosure. It does state the side effect ('Create an upload session') and the return value ('Returns upload URL'), but it does not explain that the returned URL is meant for a subsequent upload step, or any session lifecycle details. This is adequate but not fully transparent.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two short sentences with no filler. The core purpose is front-loaded and the return value is stated immediately, making it easy for an agent to parse quickly.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with no annotations, no output schema, and three required undocumented parameters, the description is too thin. It clarifies the main purpose but omits important invocation context such as file_size units, parent_id meaning, the fact that this only creates a session rather than uploading content, and what to do with the returned URL.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description needed to compensate. It only hints at file_size being relevant via the '>4MB' threshold and says nothing about parent_id or name semantics, units, or constraints. The parameter names are somewhat self-explanatory, but the description provides almost no added meaning for invocation.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Create an upload session'), the resource ('upload session'), and a specific scope ('large files (>4MB)'), while also indicating the key return value ('upload URL'). It is not explicit about how this differs from siblings like upload_file or create_session, but the size threshold provides meaningful differentiation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives an implied usage condition ('for large files (>4MB)') which helps an agent decide when this tool is relevant. However, it does not explicitly state when not to use it or mention alternatives such as upload_file for smaller files, leaving some routing to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.